Enbridge’s Line 5 pipeline transports 22 million gallons of crude oil and natural gas liquids across 645 miles of countryside every, single day — from Superior, Wisconsin through Michigan’s Upper Peninsula, under the Straits of Mackinac, and down to refineries in Sarnia, Ontario.

Whitmer had set a Wednesday deadline to shut down Line 5, contending it risks a major oil spill in the Straits of Mackinac linking Lake Huron and Lake Michigan. But Enbridge says only the federal government has authority to order a shutdown.